Two synthetic approaches were developed for the title compounds 8a-g via coupling of diazotized anilines with 7-acetyl-6-methyl-3-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine 7, and reaction of N-aryl 2-oxopropanehydrazonoyl chlorides 9 with 4-omino-3-mercapto-5-phenyl-1,2,4-triazole 1. The tautomeric structures of 8 were elucidated by their spectral analyses and correlation of their acid dissociation constants with Hammett equation.